1. Technical Field
Illustrative embodiments described in this patent specification generally relate to a fixing device and an image forming apparatus, and more particularly to a fixing device including a thermostat that can be easily installed in the fixing device, and an image forming apparatus including the fixing device.
2. Description of the Related Art
Related-art image forming apparatuses, such as copiers, printers, facsimile machines, and multifunction devices having two or more of copying, printing, and facsimile functions, typically form a toner image on a recording medium (e.g., a sheet of paper, etc.) according to image data using an electrophotographic method. In such a method, for example, a charger charges a surface of an image carrier (e.g., a photoconductor); an irradiating device emits a light beam onto the charged surface of the photoconductor to form an electrostatic latent image on the photoconductor according to the image data; a developing device develops the electrostatic latent image with a developer (e.g., toner) to form a toner image on the photoconductor; a transfer device transfers the toner image formed on the photoconductor onto a sheet; and a fixing device applies heat and pressure to the sheet bearing the toner image to fix the toner image onto the sheet. The sheet bearing the fixed toner image is then discharged from the image forming apparatus.
Although a thermostat has been widely used to prevent an excess temperature increase of the fixing device, the method for installing the thermostat in the fixing device and the position at which the thermostat is installed in the fixing device require a design that takes into consideration various restrictions, including mechanical tolerances of each component and overall safety requirements. For example, in a configuration in which an electrode plate is used for the primary circuit, the electrode plate must be spaced a certain distance apart from other metal sheet components to comply with safety standards because the electrode plate is uncoated and unprotected. Further, the electrode plate must be initially installed inside an external cover of the fixing device in order to prevent electrical shock during installation. Consequently, the various restrictions described above make it difficult to install the thermostat between the electrode plate and a housing that accommodates the thermostat after installation of the electrode plate and the housing in the fixing device.
In order to facilitate installation of a conductive plate in the housing, one example of a related-art image forming apparatus includes a configuration in which a blocking device, that is, a thermostat, is rotated at a certain angle while the conductive plate is fitted into a fitting groove in the housing to engage a terminal of the conductive plate with an engaging groove in the housing.
However, in the above-described image forming apparatus, how to facilitate installation of the thermostat is not suggested or taught. Further, because of the restrictions described previously, installation of the thermostat is not sufficiently facilitated even if the above-described configuration is applied to installation of the thermostat in the fixing device.